Nozzles of gas turbine engines carry extremely hot exhaust gas. It is therefore necessary to provide liners which protect the underlying structure. These liners are conventionally air cooled, usually with an impingement plate located adjacent the liners with cooling air passing through holes in the impingement plate and impinging against the liner. Such airflow then passes out through the aft end of the liner convectively cooling hot surfaces as it traverses aft.
These liners must furthermore be supported in such a way as to permit expansion relative to the support structure because of the temperature differential.
Even with the appropriate cooling construction these liners still deteriorate and must be replaced. Previous methods of retaining the liners produce difficult installation and replacement problems.
Fasteners previously used required welding. They also frequently required covering of the fasteners. This tended to lead to disturbances of the aerodynamic contour. They were also very difficult to remove for replacement of the liner.